Safety-stop for elevators



(No Modem n J.V G. GERDING.

Sa'xeaty Stop for Elevators! -N0Q23 5,35.4; Patented Dec.14,18so.

NJETERS PNOTC-LITHOGRAFNER, WASHINGTON. D C- UNITED STATES PATENT OFFICE.

JOHN Gr. GERDING, OF OOLLINSVILLE, ILLINOIS.

SAFETY-STOP. FO R ELWEVATORS.

SPECIFICATION forming part of Letters Patent No. 235,354, dated December 14, 188C.

Application filed April 5, 1880. (No model.)

new and useful Safety-Stop for Elevators, of

which the following is a specification.

It is well known that hoisting-machines,

' specially elevators the platform of which is hoisted by a rope, have also automatic-acting devices to stop the sudden fall of the platform,

(in ease the rope breaks) and prevent injury to life and limb, dangers, 86e.V The safetystops most generally used for the purposes stated consist of pawls or elbow-levers' con-l nected with the spring-bar of the platform, said stops being acted upon to engage vertical ratchets fixed on the inside face of `the uprights. I have found that the said named safety-stops afford only a precarious safeguard, inasmuch as the platform, in falling a distance equal to the length of-a tooth of the ratchetswhich frequently occurs in the parting of the rope-acquires sufiicient momentum-to fracture the parts by the concussion upon the pawls in catching upon the ratchets. v

My objects are, therefore, to overcome the unreliable counter-check of pawls and ratchets upon the accidental fall of the platform, by providing a more instantaneous, safe, and decisive-acting safety stop device. I attain these objects by the mechanism illustrated in the accompanying drawings, in which- Figure l is a perspective view of my entire improvements set up and ready for operation. Fig. 2 is a detail side view of that part of the platform provided'with the safety-stop, show- `ing the latter in the two positions they assume-viz., the full lines show the dogs biting into the uprights toeheck the fall of they platform', and the dotted lines show the positionv of the dogs permitting the free sliding or use of the platform. v

AA are the stationary uprights or conductors between which the platform or cage B operates. The platformconsists of the bed Bf, united by the vertical and inclined brace-rods b b to an upper cross-beam, B2. (See Fig. l.)

Also, I provide the platform `B with a bowspring, C, and secure same, by nuts and pin 'at c, between the spring-bar D and the upper cross-beam, as shown in Fig. 1. The platform or cage is therefore constructed so as to properly slide up or down between the uprghts, and has also a spring-bar to follow up the movements or action of the spring C, the said parts being the same as exist in ordinary elevators or hoisting apparatus.

The nature of my invention, however, consists in imparting the action of the spring U and spring-bar D to a novel combination of parts constituting an improved safety-stop, and as will now be described.

e e are two U-shaped plates. Each of these are bolted to the spring-bar D, so that their `ends project in line with the outer faces of the uprights, as shown in Fig. 1.

E E E E represent pairs of lever-rods, a pair or set of these rods being provided at the opposite sides of the cage or platform, and in line with the opposite outer faces of the uprights, as indicated in the principal figure. The upper end of each of the lever or connecting rods E E E E is secured to the U- shaped plates e e', while the lower end of each of said rods connects with the safetypawls or dogs F F F F. (See figures.) Two pairs or sets of these pawls or dogs are therefore provided, and each made to be a duplicate. of the other, and preferably of the construction as shown.

lo properly fulcrum each pawl or dog, I further secure to the same side of the bed of the platform the side plates, Gr G G' Gr', and cause these to project somewhat below the lower part of the platform, so that the fulcrum for each dog can be at the respective points or pivots f f j" The arrangement of each pawl or dog, as here shown, is therefore such that each can gripe or bite into the outer or contiguous face of the uprights, and each subject to the action of the spring C.

Having thus described the construction and arrangement of my improvements, together with various other parts which ai'gold, I will now describe the mode in which my safetystop operates: The tension of thehoisting rope or chain, produced by the weight of the cage or load while the machinery is in operative condition, causes each pawl or dog to assume the position shown in dotted lines in Fig. 2, and keeps them out of engagement from the faces of the uprights. The pawls or dogs, positioned as just. stated, permit the free sliding IOC np or down ot' the platform, and at same time it is apparent that the spring (l and springhar I) are pressed upward. As soon, howl ever, as the rope breaks, the spring C comes I What 1 claim isinto action, prcssingdownward the bar D and l In a hoisting machine or elevator, lever or connecting rods, the latter causing 1 or platform of which has the spring C and each pawl or dog atthe same time to gripe or l spring-bar l), the combination of the U-plates bite into the uprights,and as indicated in Fig. l e e, the connecting-rods E E E' E', the side 1 and by the full lines in Fig. 2. The downplates, G G G G', and pivoted safety pawls ward action of the spring acts, therefore, sil or dogs I" F 1*" F', to operate as and for the purposes set forth.

multaneously on all'the pawls or dogs, and these are forced to gripe or bite in the most In testimonywhereofl have hereuntosigned and instantly on the breakage of the rope, a positively self-acting safety-stop for the elevator is achieved.

the cage positive manner, making aninstantaneous and my naine. absolute stop. The locking action to arrest JOHN G. GERDING. the platform takes place on four points, (being Witnesses:

the opposite outer faces of the uprights,) and JOHN W. HERTHEL,

ROBERT BURNS.

since all the safety-pawls act simultaneously 

